Lithium Carbonate Recovery With Boron and Calcium Removal
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Solution Overview
Problem
Existing methods for recovering valuable materials from lithium-ion secondary batteries often result in lithium carbonate with high boron and calcium content, which can adversely affect the performance of lithium-ion batteries. Additionally, these methods may lead to the loss of lithium during the recovery process.
Innovation Solution
A method involving a heat treatment step at 660°C or higher, followed by crushing and classification, wet magnetic separation, acid leaching with sulfuric acid, neutralization with calcium hydroxide, calcium carbonate crystallization, and calcium adsorption using a chelating resin to recover high-grade lithium carbonate with boron content less than 1 ppm and calcium content of 100 ppm or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If acid leaching is performed on battery scraps including boron, then lithium is recovered, but boron is transferred into the acid solution and contaminates the recovered lithium carbonate
Solution Approach 1:
The patent extracts boron from the acid leachate through selective precipitation using calcium hydroxide, which forms calcium borate precipitate. This separates boron from the lithium-containing solution, allowing lithium carbonate recovery without boron contamination while maintaining high lithium recovery rates.
2Quantity of substance
If neutralization is performed to recover lithium, then lithium solution is obtained, but sodium and other impurities are dissolved and contaminate the lithium carbonate
Solution Approach 1:
The patent segments the impurity removal process into multiple stages: first removing boron through calcium hydroxide precipitation, then performing solid-liquid separation, and finally recovering lithium carbonate through controlled neutralization. This multi-stage approach prevents sodium and other impurities from contaminating the final lithium carbonate product while maintaining high recovery rates.
3Manufacturing precision
If multiple separation steps are added to remove impurities, then lithium carbonate purity is improved, but process complexity increases
Solution Approach 1:
The patent controls the pH parameter during neutralization to optimize lithium carbonate precipitation while preventing impurity co-precipitation. By carefully adjusting pH to the appropriate range and controlling the addition rate of neutralizing agent, the process achieves high purity lithium carbonate recovery without requiring excessive separation steps, thus balancing purity with process simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves a high recovery rate of high-grade lithium carbonate, efficiently recovering valuable materials with minimal impurities, thus addressing the limitations of existing technologies.
Implementation Method 1
a heat treatment step of performing a heat treatment on a lithium-ion secondary battery at a temperature of 660° C. or higher
Implementation Method 2
a wet magnetic separation step of performing wet magnetic separation on the fine-particle product slurry to separate the fine-particle product slurry into a magnetic material and non-magnetic material slurry
Implementation Method 3
an acid leaching step of adding sulfuric acid to the non-magnetic material slurry to adjust pH to 0 or higher and 3.5 or lower to leach the non-magnetic material
Implementation Method 4
a calcium carbonate crystallization step of adding CO2 to a liquid obtained at the neutralized cake solid-liquid separation step
Implementation Method 5
a calcium carbonate crystallization step of adding CO2 to a liquid obtained at the neutralized cake solid-liquid separation step
Implementation Method 6
a calcium adsorption and removal step of adsorbing and removing calcium with a chelating resin
Data Source
AI summary
Provided is a method of recovering valuable materials that is a method of recovering lithium carbonate from a lithium-ion secondary battery, where the lithium carbonate has a boron content of less than 1 ppm and a calcium content of 100 ppm or less. The method includes a heat treatment step, a crushing and classification step, a slurry formation step, a wet magnetic separation step, an acid leaching step, a neutralization step, a neutralized cake solid-liquid separation step, a calcium carbonate crystallization step, a calcium carbonate solid-liquid separation step, and a calcium adsorption and removal step.